Crankcase insulation



' Patented June 6, 1944' caanxcasr; INSULATION V V Sidney E. Kienitz, New York, N. Y., asslgnor to Pentrathane Products. 1110., Long Y., a corporation of New York Bland City NoDrawinI. Application August '12, 1941, I

r I Serial No. 406,517 2 Claims. (Cl. 117-27) My present invention relates to an insulating material and, more particularly, to aninsulating material which is sufficiently flexible and has a sufficiently high K factor and adhesion to enable its use for automotivecrankcases and in any other case where a flexible insulation is needed.

While, in the manufacture and construction of motor vehicles of various types, a great deal of emphasis has in the past been placed upon maintaining a definite maximum temperature and preventing the-oil or other fluids used in connec tion with the motor from rising above this maximum temperature, less emphasis has been placed upon the maintenance of aminimum temperature, which will ensure thebest operating emciency of the vehicle.

It is well-known, for instance, that the oil normally used in a vehicle for lubrication will have a consistency or viscosity whichwill prevent improper filtration by any filtering or cleaning means connected with the vehicle should the oil temperature be too low. x v

In cold weather, when starting a motor vehicle,

the metal parts in the vehicle haveall shrunk due to the low temperature. Therefore,'. all of the gasoline which comes from the carburetor into themotor is notconsumed but some of it passes or squirts by the rings and goes down into the crankcase and mixes withthe ,oil, causing dilution, sometimes to the extent of or per cent. Then, in addition, because of this cold condition, water vapor which is always present in the air taken into the motor through the breather of the crankcase .goes below the dew point and forms actual water. The water plus the gasoline above-mentioned plus the oil then forms into a soapy mass or sludge. The sludge remains in the crankcase and until the oil attains a temperature of at least 140 degrees F. will not break up. If it is possible to maintain a higher temperature than 140?, then the oil will begin to again pass through the filter and the sludge will break up, the dilution will evaporate and so will part of the water. Sludge is probably the most dangerous condition in automotive problems.

A great amount of radiation of heat in the ordinary motor vehicle is in the crank case itself where the oil collects. In cold weather and particularly during the winter months, the heat .in the oil may readily radiate to the outside atmosphere through the'metallic crank case, thus leading to the deleterious and adverse effects previously noted.

Various attempts have been made to provide an insulating coating for the surface of the crank casev in order to-prevent such radiation. But in every case such insulating coatings have been failures, owing not so much to the fact that they did not insulate properly, butrather because the crank case in a motor vehicle is subject to severe vibration and very great variations in temperature conditions. 7

This made it almost impossible to economically attach insulation to the crankcase itself.

* Thus, anyinsulating coating having a, sumciently high K factor which was applied to the crank case was shaken or dusted on after the motor vehicle had been in use for only a short period of time. Owing to the various stresses in the crank case itself and further owingto the vibration, the insulating material tended to crumble and fall apart. 7 1

An object of the present invention is the formation of an insulating coat for surfaces and particularly for surfaces which are in constant vibration, the said insulating coating. having a high K factor. and nevertheless being flexible and yielding rather'than friable or crumbling. Other attempts to provide an insulation which will have, the proper insulating qualities and be sumciently secure have been so expensive as to beimpractical.

I have found that'most insulating materials having the requisite insulating properties are rather of a friable or crumbly nature: and hence, if merely caused to adhere by any sizing or glue to a surface, may readily be detached therefrom by constant vibration and severe variations in temperature. This is the primary reason-for the failure of prior insulating coatings which have been employed on crank cases ofvarious kinds. A further object of this invention, therefore,

is .the combination of an insulating materialwhich may be of a friable or relatively stifi! or crumbling character with a matrix ofa plastic material which is flexible and resilient in such a manner that the matrix cushions and secures each particle of the insulating material and at the same time causes both the matrix and the insulating material to adhere securely to the surface to be-insulated. I

A further object of this invention is the provi sion of a plastic, flexible, insulating coat comprising a quantity of insulating material dispersed in a matrix of flexible plastic adherent material in such a manner that it may yield readily to severe vibrations and severe changes in temperature of the surface to which it is attached, and in such manner that it will remain attached to temperature. and so that it will resist weathering.

Still another object of the present'invention. is the provision of an adherent, resilient, flexible. plastic insulating .coating for a surface, said coating consisting of finely-divided insulatingmaterial, such as vermiculite, embedded in a matrix-of rubber, the said rubber matrix position ing and encasing each of the particles of the vermiculite in order to form an insulating mass and also providing auadherent surface'for securement to the surface upon which the coatin istobeplaced, f g

Another object of the present invention is a method for securing an insulating plastic, resilient, flexible surface or coating to a surface which istobeinsulated.

These and many otherfobjects ofthe present invention will in part be apparent and, where not apparent pointed out in the ,'foll0wing description: U

One example offan embodiment of 'my invention consists offa' plastic coating for a surface wherein the coating consists primarily of powtiered vermiculite embedded-in a rubber matrix formed from aIpre-vulcanized latex such as Vultex. The rubber matrix'encases and positions each particle of vermiculite-to form a substantially continuous'ins'ulating coating," the rubber latex also serving to cause the coatingtoadhere "to the surface to be insulated. f g

In the'actual preparation of th ma'terial for application toa'surface to be insulated. I first screen the vermiculite to remove the roughv particles, particularly where the insulating coatin is to be of the'order' of only%" in thickness.

Should a thicker'fcoating be necessary. then coarser'particles'may be used. But, in the case 'of ordinary crank case insulation.- I have found that a coating over the outer surface is sufflcient.

I then prepare a solution of pre-vulcanized latex consisting -of 30%" solids and 70% water.

Ordinarily; the pre-vulcanized latex is securable in commerce as in the form, for instance, of Vultex which consists of a 60% solution of latex in water. A

I dilute this solution sothat the proportion of water therein is 70%. I then add a retarder to the liquid latex solution, the said retarder preferably consisting of a casein which is "added in anamount of the order of 1% by volume to the solution. The retarder may be procu rable as an ordinary article of commerce in the form for instance of Cascd' cement.

The retarder is notabsolutely-essential to the "formation of the plastic coating but I have found that while the plastic coating hereinafter de-- scribed will ordinarily set in minutes and'thus present's problems in its application, the addition of the retarder delays the setting'time -by one hour and thus allows sufficient time for thecoatingtobe applied.

Hence, while the retarder is not essential to the insulating coating which is eventually to be formed. it is, in ordinary'practice, quite necessary to use the retarder in order to permit the working and formation of the insulation.

I then combine the vermiculite and the solution above noted as follows: To one-half gallon of the pre-vulcanized latex casein solution I add 22 ounces of powdered vermiculite. The powder is stirred slowly into the liquid and is thoroughly combined therewith. The mixture is then ready for application and the application thereof should be completed within one hour after the mixture has been formed.

It is essential that the powder be stirred or poured into the liquid. If the reverse operation were performed, simply a ball of rubber would be obtained, since the rubber would then start to oxidize in the air and would dehydrate.

All of the foregoing operations are performed atnormal atmospheric temperatures.

In actual commercial use, I prepare the liquid solution of pre-vulcanized latex or Vultex" and casein in the proper proportions and package these 'in half-gallon cans. I also prepare 22- ounce packages of powdered vermiculite. The

materials for the insulating coating are thus prepared and packaged in separate form.

The consumer, when he is ready to apply the coating, stirs the powdered vermiculite into the liquid solution and spreads the material on the surface to be insulated with a knife or a spatula or with his'hands.

. ."Normally, I have found that a thick coating provides sufficient insulation 'for an automobile crankcase.

The coating sets within one-hour to a condition where it is a relatively solid mass and achieves a sufficiently complete set in four hours to permit its use. In twelve hours the final set is achieved and the insulating coating has reached its fullest K factor.

"Theinsulating coating, when it has set, consists of powdered insulating material such as vermiculite embedded in a rubber matrix formed by the pre-vulcanized latex solution.

The embedding of the powdered vermiculite in i the rubber-matrix ensures that all of the insulat-.

ing material will always be adherent to the surface and the rubber matrix itself is adherent to the surface, thus causing the entire mass to adhere. I

Owing to the embedding of the insulating material in the flexible rubber matrix, the insulating coatingis resilient and flexible and will yield readily to any vibrational forces rather than crumble by reason thereof.

,The preparation of this type of coating in this manner and the embedding of the insulating material in the rubber matrix by the method herein set forth permits the utilization of any type of insulating material in powdered form no matter how friable or crumbly the same may be.

Thus, the] disadvantages of prior insulating coatings for crank cases are obviated since the material cannot crumble nor can particles thereof be torn away by vibration.

Inthe actual preparation and securernent of the insulating coating to a crank case, I have found that the best results are achieved by placing a thin film of cement or glue on the crank case surface before the coating is applied in the manner above set forth.

The coating is thereafter applied and adheres to the surface not merely by reason of adhesion of the latex but also by reason of the cement. This After the coating is applied and has set, I have found that best results and protection from mud and weathering may be obtained by shellacking the surface, and, specifically, I have obtained the best results by use of two coats of an orange shellac.

The K factor of the insulating coating may be improved by the addition of more insulating particles or materials. However, the proportions above set forth have been found by experiment to be the best.

The more vermiculite there is in the coating, the greater the insulating powers and the more latex found in the coating, the greater the adhesive powers. Hence a compromise must be effected between the two and sufficient latex is used to ensure the adherence of all of the particles of vermiculite to the coating so that the same will not powder or dust off.

I have found that the K factor of the insulating coating formed on a cranl; case in the manner above described is higher than that of any other plastic insulation which is .used for severe vibration.

It will not crumble, rupture, or break apart and can, if desired, be removed in warm weather, though I have found that best results are obtained by leaving the insulation on the crankcase permanently.

In the actual application of my insulating coating to a crankcase, I have found that his best to apply the coating toawarm crankcase and the best results are obtained by leaving it in a warm atmosphere with good air circulation.

Additional coatings of my insulating material may be applied on top of prior coatings.

In some forms, I have found that a mixtur of powdered vermiculite and powdered concrete produces the best results. It should be remembered that many other types of powdered or fibrous insulating materials may be utilized in the coating and dispersed within the rubber matrix in the manner above described.

In the winter time, in the use of automobiles on start-stop vehicles, oil will rarely warm up to the optimum operating temperature. Oil will not function properly in a motor vehicle unless it reaches a temperature of 140 F.

Many instances'have occurred in which not even an oil temperature of 90 F. has been reached in the winter.

Various tests with crankcases protected by my insulating surface have shown that the heat imparted to the oil by the engine and by the circulating water is retained so efliciently in the crankcase (when my insulating coating is used) that the minimum safe operating temperature of 140 F. for the oil is very quickly reached and very efficiently maintained.

In addition to utilizing other forms of insulating material as insulating particles to be dispersed in the matrix, various other types of adherent, flexible, yielding materials may be used to form the matrix and I am not necessarily limited to pre-vulcanized latex. Other types of latex may be used and other plastics of a yielding resilient adhering material may be used.

Primarily my invention is intended for use in the insulation of crankcases for automotive -vehicles, since in such uses the most severe vibrations occur and hence make necessary a plastic, resilient, yielding, flexible, adherent coating which will not crumble or easily be removed. However my insulating coating may obviously be as readily used in connection with other types of insulating problems and may, for instance, be used as pipe insulation, wall insulation, container insulation or for other insulation purposes.

While I have herein set forth the proportions which I have found useful for obtaining optimum results both with respect to insulating properties and flexibility and adherence, it must be remembered that these results are obtained by a compromise of all of the elements of the coating.

Greater insulating properties might be ob tained if the avoidance of crumbling were not an important problem or if adherence and flexibility and resilience were not important. And of course greater adherence, resilience and flexibility might be obtained where insulation is not important.

Thus, the quantities may be varied in accordance with the particular use desired. 7 For purposes of use in connection with crank case insulation the foregoing proportions have however been found to be the best compromise to produce results which are commercially acceptable. V

In describing my invention,'I have necessarily set forth but a few illustrations of the basic principles involved.

Many other elements of my invention should now be obvious to those skilled in the art and many variations and modifications thereof should also be clear.

Accordingly, I prefer to be bound not by the specific disclosures herein but only by the appended claims.

I claim:

l. The method of forming an adherent, resilient, flexible insulating coating for the surface of a crankcase, comprising the steps of stirring 22 ounces of powdered vermiculite into one-half gallon of a 30% suspension of pre-vulcaniz'ed latex, spreading the mass thus formed upon the surface and permitting the mass to dry.

2. The method of forming an adherent, resilient, flexible insulating coating for the surface of a crankcase, comprising the steps of stirring 22 ounces of powdered vermiculite into'one-half gallon of a 30% suspension of pre-vulcanized latex containing 1% by volume of casein,'spreading the mass thus formed upon the surface and permitting the mass to dry.

SIDNEY E. KIENITZ. 

